Dishwasher Requiring No Added Detergent/Rinsing Agent/Softener

ABSTRACT

A program-controlled dishwasher that is to be operated with combined preparations comprising several active substances as detergents is provided. The dishwasher is configured so as to be free from softening systems and/or dosing devices.

The invention relates to a program-controlled dishwasher that is to be operated with combined preparations.

Program-controlled dishwashers generally have the program steps “pre-wash”, “clean”, “intermediate wash”, “final rinse” and “dry”. The detergents needed for operation of dishwashers increasingly include so-called “2 in 1” or “3 in 1” combined preparations. They generally consist of a detergent substance, a rinse-aid substance (2in 1) and additionally if necessary a softener substance (3 in 1). The combined preparations can be obtained both in the form of a compressed tablet, known as tabs, and in the form of a powder. The user puts the combined preparation into a washing container of the dishwasher before activating the wash program. Depending on the preparation and on the specifications by the manufacturer of the preparation, it is put either into a dosing apparatus of the dishwasher or directly into the washing container, for example in the cutlery basket. The combined preparations with their various active substances are then available, essentially from the start of the wash program, to clean the dirty crockery or objects to be washed placed in the dishwasher and with their additional functions, especially softening and final rinsing.

Although all active substances are added to the cleaning process from the outset, they should start working at different times in the wash program. For example, the active substance “rinse aid” is not required until later, i.e. in the “final rinse” subprogram step. To ensure that the various active substances in the combined preparation each start to work at the relevant time within the wash program, combined preparations essentially make use of two principles:

According to the “retardation” or “dilution” principle the active substances which are required at a later stage of the wash program are included in an especially high concentration in the preparation. It is assumed here that thanks to the active substance adhering to the objects to be washed, the washing container walls and the container lining a sufficient concentration of the active substance, e.g. of the rinse aid, is still present in the rinsing liquid at the time it is required to work in order to achieve the desired cleaning effect.

According to another principle, namely that of “encapsulation”, those active substances which are not to be used until a later time are encapsulated, for example in a wax casing. The casing does not start to gradually dissolve, depending on the temperature and/or pH value, until during execution of the wash program. Thus once the first cleaning stages have finished the encapsulated active substance, e.g. rinse aid, is not available in the program run until a later time, e.g. in the “final rinse” subprogram stage.

The object of the present invention is to specify a dishwasher which uses such combined preparations and is cost-effective to manufacturer.

This object is achieved by a dishwasher having the features of claim 1. The inventive dishwasher is, in accordance with the characterizing features of claim 1, designed to be free from softening systems and/or dosing devices. The dishwasher consequently merely includes a washing container within a housing with its basic functions, a heating unit and a circulating pump for the rinsing water, storage containers for the cutlery, and spraying devices inside the washing container. Thus a dishwasher is specified which can be operated as required and successfully with the commonly encountered combined preparations. By dispensing with softening systems and/or dosing devices the dishwasher can however be manufactured significantly more cheaply and is less prone to operating errors on the part of the user. In addition, the maintenance effort required for such a dishwasher is greatly reduced compared to conventional machines because of its simpler fittings and by dispensing with complex adding and dosing devices.

Domestic appliances are subjected to tests by different institutions in different areas. For example, in the European Union domestic appliances must be subjected to tests designed to produce information about the energy consumption of the respective domestic appliance in relation to its output. The result of the test is documented in a certification mark. For domestic dishwashers connected to a cold water supply, the stipulated test procedure and precise quantities of active agents are laid down, for example, in an EU standard. The standard is initially based on dishwashers with dosing devices and softening systems. If no softening system is present in the dishwasher, the manufacturer must specify a maximum permissible water hardness for the operation of the machine. A separate test for dishwashers without a dosing device is not provided for, nor does it make sense to perform one, since there is a lack of comparability. The test cannot therefore be based on combined preparations. Testing dishwashers for operation with combined preparations as rinse-aid is thus not possible. In addition, in many states of the European Union these preparations only attain a market share of 10 to 15%. In contrast, in Germany they already have a share of around 50%, based on their ease of use. Hence it is desirable to have a device available with which it is possible to test the inventive dishwasher, for example in accordance with an EU standard.

According to an advantageous embodiment of the invention the dishwasher can hence have a display device which indicates the dosing time or if appropriate several dosing times for manual dosing of active substances during the program run. Since the proposed dishwashers do not have a dosing device which ensures the addition of active agents at the requisite time, the addition must be simulated. A separate device could indeed be provided for this in the factory. However, the design effort required for this is not worthwhile for just one test run or a few test runs for each type of machine. Hence the active substances are to be added manually by a tester during the test run. Preferably the inventive dishwasher therefore has means which display the dosing time of active substances. So that the addition can take place at the requisite correct time, the inventive dishwasher has for example a corresponding display device. For the addition of several active substances, for example of a detergent after a pre-wash procedure or of a rinse-aid prior to a drying procedure, it may be necessary to display several dosing times. In what follows, for the purposes of simplification, only one dosing time is assumed, but this should include the possibility of several dosing times.

Indicating a dosing time by means of the display device does not entail any considerable design effort, so that the cost advantage of the dishwasher is not significantly impaired. Thus dishwashers designed to operate with combined products can also be subjected to a test in accordance, for example, with an EU standard. Because of the quantities of active substances laid down therein the inventive dishwashers also contain no more active substances during the cleaning process than stipulated in the standard. Although the quantities stipulated in the standard do not absolutely reproduce the actual circumstances of normal or everyday operation with combined products, comparability is assured.

The water hardness requires separate consideration. Where in conventional dishwashers a softening system is operated, a salt must be added to it from time to time in order to regenerate the active substances of the softening system. In contrast, the combined preparations are based on a different principle. A chemical, e.g. phosphate, is added to them, which in itself exerts a softening effect on the rinsing liquid, e.g. absorbs calcium ions. However, it is not automatically available on the market. Hence either an external water softening system can be made available for testing the dishwasher in accordance, for example, with an EU standard, or a maximum water hardness can be stipulated for the test run in separate instructions from the manufacturer.

Whereas in conventional dishwashers a controller ensures the requisite dosing time for the detergent, in the inventive dishwasher this time is to be adhered to by the tester. Hence it must be ensured that the dosing time is notified to the tester beyond doubt. Another advantageous embodiment of the invention can hence be envisaged in that the dishwasher has a mechanical display device for the program run, which indicates the dosing time, especially optically. Above all an analog display of the program run provides an easily readable display of information. It informs the observer not only about the current dosing time, but also announces it in advance. This is especially advantageous for dosing at the correct time. Indication of the dosing time can moreover also be supported acoustically in the case of a mechanical display. Thanks to the low-cost mechanical display it is consequently ensured that the active substances can be added at the correct time in the test run.

According to an alternative embodiment of the invention a dishwasher can have an electronic display device for the program run, which indicates the dosing time optically and/or acoustically. Thus the program run and in particular the dosing times are indicated virtually unmistakably.

As already explained, the display of the dosing times is required only for testing the dishwasher in accordance with, for example, an EU standard. In a further advantageous embodiment of the inventive dishwasher the display of the dosing times can hence preferably be activated and/or deactivated in the factory. The additional information concerning the dosing times is in fact no longer necessary for the normal use of the dishwasher and could cause confusion in normal operation. Depending on the nature and type of the display device, an additional device can therefore be added merely to the machines to be tested in order to display the dosing times, or each machine can be equipped in the factory to display the dosing times, the display being deactivated in the case of dishwashers which are not to be tested, or not activated in the first place.

According to another advantageous embodiment of the invention the dosing times are accommodated e.g. on a foil or sticker on the housing, for example preferably detachably on the display device. The dosing times are, for example, indicated in minutes after the start of the program. This provides a simple opportunity of preparing a dishwasher for a test in accordance with, for example, an EU standard, without having to make technically complex modifications compared to standard products. With a detachable foil or another printed or specified means the dishwasher can also be converted without great effort for normal operation with combined preparations. It can be used with a mechanical as well as an electronic display. The indication of the dosing times which is no longer required in normal operation and which thus causes confusion can thereby easily be eliminated.

For the same purpose, in the case of an alternative embodiment of the inventive dishwasher, the optical or acoustic indication of the dosing times can be linked to or dissociated from a display device, preferably in the factory. In the case of electronic indication, activation or deactivation can be effected especially simply by means of a switch. Electronic indication too can be used in the case of both a mechanical and also an electronic display device.

For the sake of completeness, it is also pointed out there that the use of the indefinite article “a” or “an” does not rule out that more than one of the features in question can also be present. 

1-8. (canceled)
 9. A program-controlled dishwasher for operation with combined preparations, the dishwasher comprising: a washing chamber in which items to be washed are disposed; and means for receiving a combined detergent preparation that is a selected one of a 2 in 1 combined preparation, a 3 in 1 combined preparation, and a combined preparation other that a 2 in 1 combined preparation and a 3 in 1 combined preparation, the dishwasher being configured to be without at least one of a softening systems and a dosing device for dosing detergent.
 10. The dishwasher as claimed in claim 9, wherein means are present which display the dosing time of active substances.
 11. The dishwasher as claimed in claim 10, wherein a display device which indicates a dosing time for manual dosing of active substances during the program run is present.
 12. The dishwasher as claimed in claim 11, wherein a mechanical display device displays the dosing times optically and/or acoustically.
 13. The dishwasher as claimed in claim 11, wherein an electronic display device for the program run indicates the dosing times optically and/or acoustically.
 14. The dishwasher as claimed in claim 13, wherein the display of the dosing times can preferably be activated and/or deactivated in the factory.
 15. The dishwasher as claimed in claim 14, wherein the dosing times can be applied to a printed or specified means, e.g. a foil or a sticker, on the housing, especially on the display device.
 16. The dishwasher as claimed in claim 14, wherein the optical or acoustic indication of the dosing times can preferably be linked and/or dissociated in the factory. 